1. Filter of the Invention
The present invention relates to a water treatment method for use in a post-mix beverage dispenser.
2. Description of the Background Art
In some locations, water sterility is a health issue, and restricts the use of on premise beverage preparation machines (generally referred to as xe2x80x9cpost-mixxe2x80x9d equipment). Where water is to be used in beverage preparation, excessive bicarbonate hardness is undesirable, since it reduces the acidity of the beverage and affects taste. Volatiles in water, such as organics and chlorine also can have an affect on its taste. Particularly hologenated organics (trihalomethanes, generally described as THMs) have recently given rise to consumer concerns and regulatory restriction. Suspended matter and turbidity reduces the quality of water both when consumed alone, and on mixing to produce a beverage. Finally, in certain locations, consumers have also shown concerns regarding the heavy metal content of water, and this too has been the subject of legislation in some countries.
Dissolved air in raw water, although not in itself a water quality aspect, can reduce the effectiveness of carbonation in post-mix equipment, and make dispensing difficult due to foaming. A means of deaerating water is advantageous for such equipment. It is noted that water deaeration is always carried out prior to carbonation in bottling and canning plants.
Therefore, a simple method for in-house, or in-store, removal of microbiological contamination, bicarbonate hardness, volatile organic compounds (VOCs) xe2x80x94particularly THMsxe2x80x94as well as chlorine and heavy metals, is important for meeting certain consumer concerns, raising the quality of drinking water in some locations, and improving the taste of on premise prepared beverages in certain outlets. Additionally, deaeration of water is highly desirable for post-mix outlets, and can lead to reduced foam on dispensing and better beverage quality. However, on premise water treatment systems must meet the following criteria:
Low cost of original equipment;
High reliability in absence of technical monitoring or controls;
All the above-stated quality criteria (i.e. sterility, bicarbonate hardness, chlorine, THMs/VOCs, turbidity, heavy metals and desirably, deaeration);
Simple, convenient, safe operation by non-qualified people (i.e. in-store or in-home);
Low cost of maintenance and operation; and
Low space-utilization.
Currently available systems for use in-home and/or in-store do not meet all the quality and other criteria. Such systems include carbon filtration systems. These systems only address chlorine and VOCs/THMs, but organics are effectively removed only when the filter is regularly maintained. When maintenance is poor, such devices can actually act as biological contaminators. Thus, carbon filtration systems can cause problems in one area while inadequately addressing other areas.
Another conventional system uses reverse osmosis. Such a system addresses bicarbonate hardness, heavy metals and microbiological contaminants only. Reverse osmosis systems require significant maintenance. Moreover, VOCs/THMs are not treated and these together with chlorine, can actually damage the reverse osmotic membrane and reduce its effectiveness.
Simple ion-exchange systems are also known. These systems normally address only bicarbonate hardness or, if more complicated, the total metal and salt content of water. However, these systems need regular maintenance such as the regeneration of the ion-exchange resin. If such maintenance is not carried out, these systems can actually produce treated water of worse quality than untreated water. Chlorine is untreated and can damage the ion-exchange resins in these systems. Moreover, VOCs/THMs are untreated and microbiological contaminants are not only untreated but may actually be significantly increased due to microbiological growth on the resin.
Simple filtration has been used where turbidity is a water quality issue. Such filtration addresses this criteria only, and can increase microbiological contamination if not regularly maintained.
Water sterilization systems using chemicals are known. Such systems address only the microbiological contaminant criterion and need careful maintenance to ensure that chemicals cannot pass into the treated water.
None of these above-mentioned conventional systems are easily maintained by the non-expert user. Moreover, all of these systems have significant penalties if the user fails to carry out proper maintenance. Although none of the above-mentioned systems meet the whole set of quality criteria discussed, all but the simplest and least reliable are costly both to buy and maintain.
U.S. Pat. No. 4,844,796 to Plester teaches the principles of heat treating water. This system, however, includes carbon and sand filtration in a first cartridge section and further filtration and an activated carbon screen in a second cartridge section. It is desired to avoid such filtration and to expand the water treatment quality criteria.
Accordingly, it is a primary object of the present invention to provide an improved method for treating all the water quality criteria named (i.e. microbiological contamination, bicarbonate hardness, VOCs/THMs, chlorine, turbidity and heavy metals).
It is a further object of the present invention to provide a method which is simple, cheap, compact, involves low and non-expert maintenance and has no water quality risk if the user does not properly maintain the system.
In this regard, it is a further object of the present invention to provide a method wherein the user is forced to take steps to maintain the system.
A further object of the present invention is to provide a method wherein the apparatus remains hot until treatment is completed to thereby avoid microbiological recontamination.
These objects are also fulfilled by a method of treating water for use in a post-mix beverage dispenser comprising the step of providing a housing having a collector, an inlet, an outlet and a head-space. The housing defines a water treatment chamber and receives water through the inlet. The method further comprises the steps of heating the water in the water treatment chamber for a predetermined period of time to break down bicarbonate hardness in the water and providing a collector on which precipitates from the water can be deposited. Gases disentrained from the water are collected in the head-space of the housing and water from the outlet is received in a storage tank. The method further comprises the step of keeping the water stored in the storage tank out of contact with air or other gases in a headspace of the storage tank by providing a collapsible water chamber including a movable hermetic barrier contacting the water in the storage tank and capable of following changes of water volume in the water chamber.
Moreover, these objects are fulfilled by a method of treating water for use in a post-mix beverage dispenser comprising the steps of introducing water into a housing, the housing having a collector and a head-space and heating the water in the housing to break down bicarbonate hardness in the water. Carbonates are deposited on the collector and heavy metals are codeposited on the collector due to change in pH of the water. The method further comprises the steps of collecting gases disentrained from the water in the head-space of the housing and maintaining the water in the housing for a predetermined period of time. The water is heated during at least the predetermined period of time. The water is then supplied from the housing to a storage tank and the water stored in the storage tank is kept out of contact with air or other gases in a headspace of the storage tank by providing a collapsible water chamber including a movable hermetic barrier contacting the water in the storage tank and capable of following changes of water volume in the water chamber.
A method for satisfying these and other objects further comprises the step of introducing water into a housing or cartridge, the housing having a collector and a filter. The filter has a shorter useful life than the collector. The water is moved through the housing with the water first flowing through the collector and then through the filter. The method further includes the step of heating the water in the housing to break down bicarbonate hardness in the water thereby depositing carbonates on the collector. The carbonates gradually reduce proper functioning of the collector. A condition of the filter which changes as a function of the depositing of said bicarbonates thereon which will eventually block the flow of water through the filter is monitored. The collector will only partially be blocked when the filter is completely blocked such that water could flow through the collector but the flow of water through the collector is prevented by the blocking of the filter. This blocked filter will therefore signal the need for maintenance of the collector.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.